iPSC cardiomyocyte recordings on QPatch II with success rates of up to 50%

Induced pluripotent stem cell (iPSC) technology has created exciting new opportunities for cardiovascular research by providing a new platform to study the mechanisms of disease pathogenesis and evaluate cardiac drug safety.

For automated patch clamp (APC) assays the potential of human iPSC-derived cardiomyocytes (hiPSC CMs) in drug development, as well as in drug toxicity testing, has been hindered by the lack of robust and reproducible APC assays and broad use of hIPSC CM APC assays is yet to be achieved. However, knowing their critical importance we have worked hard to optimize sample preparation and assays to efficiently work with human hiPSC CMs.

Cav, Nav and hERG currents were recorded, as well as action potentials. In the initial experiments, we obtained up to 50% success rates and went on with more challenging, complex and longer experiments that included pharmacology, which understandably reduced success rates, but provided even more conclusive and useful data.

Below you can take a sneak peek of data examples on Cav1.2 currents and action potential recordings. The data was obtained as part of a collaboration with Professor Niels Voigt and his group at University Medical Center Göttingen, Germany.

Figure 1: APC (QPatch II) studies of Cav1.2 currents in hiPSC-derived cardiomyocytes (hiPSC CMs) in physiological Ringer’s solution. Left: The success rate, in the percentage of 48 experiment sites, of successful experiments (black bar) and of CMs with a voltage-dependent Ca2+ (Cav) current (ICav < -100 pA, grey bar). Error bars are SD of NQPlates = 3. Middle: Representative Ca2+ current traces elicited across a range of voltage steps (from -40 to +60 mV), before (black) and after (red) the addition of 10 µM nifedipine. Right: Cav current density as a function of voltage before (black) and after (red) the addition of 10 µM nifedipine. Data points are AVG ± SD of NCells = 28.

Figure 2: APC (QPatchII) measurements of paced action potentials in hiPSC-derived cardiomyocytes (hiPSC CMs) in physiological Ringer’s solution. Top left: The success rate, in percentage of 48 experiment sites, of successful experiments (black bar) and of CMs with paced action potentials (grey bar). Error bars are SD of NQPlates = 2. Top right: Example of spontaneous action potentials recorded in iPSC CMs. Bottom left: Average resting membrane potential (RMP) in CMs with paced action potentials. Error bars are SD of NCells = 7. Bottom middle: Paced action potential before (black) and after (red) addition of 10 µM nifedipine. Bottom right: The action potential duration at 90% (APD90) was calculated and plotted before (black bar) and after (red bar) addition of 10 µM nifedipine. Error bars are SD of NCells = 7.

Stay tuned. An application report will follow soon.